Leveraging C# features for recursion

C# offers several features that can make writing recursive functions easier and your code cleaner. Two of these features are local functions and pattern matching.

Local functions

Local functions allow you to define functions inside the body of another function. This can be particularly useful for recursion when you want to encapsulate all the logic within a single method, keeping the recursive part separate for clarity and maintainability.

Here’s an example showing how to use a local function for recursively processing video categories and counting videos:

void ProcessAndCountVideosInCategory(Category category)
{
    int videoCount = 0;
    // Local function for recursion
    void CountVideos(Category cat)
    {
        foreach (var subcategory in cat.Subcategories)
      {
 ...